Study On Desulphurization Of High Sulfur Bauxite In The Process Of Dissolution

In recent years,the aluminum industry in our country has sustained and rapid development,and the demand of bauxite resources market is brisk.With the increase of alumina production in China and the shortage of high-grade bauxite resources in China,the degree of dependence on foreign high-quality bauxite has reached more than 50%.The high sulfur bauxite in China is rich in reserves and most of its grade is high.It is suitable for Bayer production.Because of the harm of sulfur,it can not obtain better industrial application.Therefore,speeding up the development of desulfurization technology for this part of high sulfur bauxite will greatly alleviate the ore supply crisis in China,and is of great significance to the development of Chinese aluminum industry.This paper takes Guizhou Zunyi area of high sulfur bauxite as raw material,in the optimization of stripping process based on the research respectively affect the dissolution process of single compound desulfurization agent,desulfurizing agent for ore desulfurization,comparing their technical and economic index.By blending ore,the ratio of Al to Si of high sulfur bauxite is about 7.3,and the content of sulfur is more than 0.7%,and the content of alumina reaches about 65%.Among them,aluminum is mainly diaspore,the presence of sulfur mainly in the form of pyrite;silicon mainly exists in quartz;a small amount of kaolinite exists;titanium mainly exists in the form of anatase.Based on the thermodynamics of dissolution,results show that the reaction temperature is 200?~300?,bauxite is easy to react with NaOH solution,with the increase of temperature and reaction degree more thoroughly;pyrite reaction with NaOH solution and increases with the increase of reaction temperature.Dissolution kinetics analysis shows that: in the experimental temperature range(200?-280?),alumina and sulfur in high sulfur bauxite stripping process with the unreacted shrinking core model in the control of proliferation,dissolution kinetics equation is 1-(1-X)2/3-2/3X=kt=Ae-E/RTt,alumina reaction activation energy is 14.20KJ/mol,sulfur the reaction activation energy is 15.50KJ/mol.Therefore,appropriate to reduce the temperature,increasing the alkali concentration,timely put forward a temperature of 250?,alkali concentration of 255g/L,lime dissolution process optimization of adding 6%,time 70 min,without affecting the aluminum dissolution rate at the same time,reduce the dissolution rate of sulfur.With the increase of mineral dissolution of sulfur content in the process of alumina digestion rate unchanged,sulfur dissolution rate increased gradually.In the optimization of dissolution process,research on desulfurization effect of single desulfurizer showed that the addition of barium 100% aluminum for processing high sulfur bauxite sulfur content of less than 1.1%,sulfur leaching rate can be reduced from 18.4% to 11.31%;add 10% ZnO more suitable for processing sulfur in high sulfur bauxite under 1.1%,and can be the rate decreased from 18.4% to 11.15% the dissolution of sulfur.In the optimization of dissolution process,research on desulfurization effect of compound desulfurizer showed that when barium aluminate content is 40%,Zinc Oxide added 10% compound as additive when processing high sulfur bauxite sulfur content is 1.1%,the rate can be reduced from 18.4% to 10.87% the dissolution of sulfur,compared with the better desulfurization effect of aluminum acid alone barium and Zinc Oxide.Through the analysis on the economic results in optimization of desulfurization technology,the dissolution of adding 40% barium aluminate and 10% Zinc Oxide compound desulphurization process,suitable for processing high sulfur bauxite sulfur content is 1.1%,the dissolving rate of 95.73%,sulfur leaching rate is 10.87%,the production of 1 tons of alumina required desulfurization cost is 68.3 yuan.